1. Technical Field
The present invention relates to a structural element that provides load bearing support and the method for, the production of same. In particular, an encapsulated polystyrene structure serves as a load bearing material for use in protecting against accidental spills and leaks associated with any type of storage, tank, or vessel.
2. Description of Related Art
During the production of oil and gas from an underground well, it is common for water to be produced along with the oil or gas. This water, called “produced water,” is typically separated from the oil or gas at the well site and temporarily stored in an above-ground storage tank, or AST (or combination of ASTs). The produced water varies in quality from one well to the next, and it can have high quantities of minerals, salts, oil, gas, sand and other substances dissolved, mixed or suspended in it. Produced water with a high concentration of impurities can be corrosive to the walls and ancillary piping of an AST and it can be toxic to the environment. A vehicle with a large storage tank attached to it periodically travels to the well site and transfers the produced water from the AST to the storage tank or vessel on the vehicle.
FIG. 1 illustrates an AST 100 with an input stream 18 and an outlet stream 20. The flow rate of the outlet stream 20 is manipulated by way of a valve 22. The produced water travels from the underground hydrocarbon bearing formation 6, up the oil or gas well bore hole 4, into what is known as a “Christmas tree” 10, which is an assembly of valves, pipes and fittings used to control the flow or oil and gas from a well. The water separating section 14 of the Christmas tree 10 directs the produced water to the AST 100. Other separating sections 12 direct the oil or gas into a pipeline 16, which transports the oil or gas to other locations for further processing or sale. A manway entrance 350 enables a technician to view the interior of the storage tank and inspect the tank for leaks, while the plumbing connections 380 to the storage cavity of said tank enable pumping of the contents therein. As seen in the side view in FIG. 1, the manway 350 extends below the bottom of the tank.
Accidental spills or leaks can occur for a variety of reasons. For example, FIG. 2 illustrates the AST 100 of FIG. 1 after the produced water has corroded the walls of the tank, creating a hole 26 in the wall of the AST. The hole 26 allows the produced water to spill or leak out of the AST 100 and onto the ground 2. In order to protect the environment from an accidental discharge such as the one illustrated in FIG. 2, approved ASTs are typically required to retain any and all fluid such that contaminate are prevented from entering the environment surrounding the well site. Fluid accumulates within ASTs and secondary containment systems from multiple sources including natural and accidental leaks or spills. ASTs usually need to have the capacity and strength to hold at least 150% of the volume of the AST, or for an array of ASTs, 150% of the largest AST in the array.
Currently, protection for the tank, soil and equipment in the containment of the top soil involves the use of a grade band of metal filled with pea gravel below the containment tank. The grade band metal is typically bolted together to form a base greater than the diameter of the containment tank it supports. The diameter of the support structure (base and pea gravel) is typically 3″ to 6″ greater than that of the AST being supported and allows for the AST to sit approximately 3″ to 6″ in height off of the floor of a secondary containment area. This allows the AST or containment tank to be at a level greater than the ground level and aids in the slow deterioration of the tank due to any standing fluid within the secondary tank area, whether the fluid is natural (such as rainwater) or accidental (spills or leaks). The pea gravel currently used is naturally porous and allows for the absorption for any number of contaminants (i.e., oil, salts, acids, etc.) that come into contact with the gravel, causing permanent contamination, which still tends to spill out of the gravel upon oversaturation. Attempts to treat or wash out the contaminants are costly, difficult, and to-date, ineffective.
Consequently, a need exists for a more efficient, effective, and convenient method for building an improved tank base to provide for safer environment and green waste. There is a need for an improved tank base, capable of being steam cleaned of any contaminants to provide more environmentally friendly standards while maintaining other advantages of a tank base and reducing costs associated with maintenance or replacement of failing tanks. There is also a need for a tank base that provides for a more efficient and cost-effective means of the shipping, transporting, and installation into customer sites. Further, there is a need for a method which keeps out moisture, preventing the proliferation of bacteria which often causes erosion of tanks from the inside out.